Crystal heater and regulator



March 1, L, YOUNG ET AL CRYSTAL HEATER AND REGULATOR Filed Feb. 1, 1936 3 Sheets-Sheet l Hum INVENTOR. 1 LLOYD L.YOUNG AND JAMES L. FINCH MfAC'I/RY M g r0 COW/W01 (MCI/l7 M l ATTORNEY.

March 1938. L. L. YOUNG ET AL I 2,109,374

CRYSTAL HEATER AND REGULATOR Filed Feb. 1, 1936 5 Sheets-Sheet 2 MERCY/f? Y INVENTOR. LLOYD L. YOUNG AND BY JAMES L. FINCH ATTORNEY.

March 1, 1938. L. YOUNG ET AL 2,109,874

CRYSTAL HEATER AND REGULATOR Filed Feb. 1, 1936 5 Sheets-sheet 5 Jay. 7 1Z 8 INVENTQR.

LLOYD L.YOUNG AND JAMES L. FINCH ATTORNEY.

"Patented M 1, 193 i 2,109,874

UNITED STATES PATENT OFFICE 2,109,874 CRYSTAL HEATER. AND REGULATOR Lloyd L. Young and James Leslie Finch, Patchogue, N. Y., assignors to Radio Corporation of America, a corporation of Delaware Application February 1, 1936, Serial No. 61,865

10Cla1ms. (c1. 219-49) This invention relates to the art oi radio frefunctional arrangement of the temperature regquency control and. deals. specifically with the ulating system of Figure 2,

regulation of temperature control of piezo-elec- Figure 4 is an enlarged detailed sectional view tric crystal ovens or containers. showing the method of insulating the heater 5 An object of this invention is to simplify and wires within the container, 5

improve the' temperature regulation 01' piezo- Figure 5 is a sectional view of the heater arelectric crystal holders. rangement shown in a modification of Figure 1,

Another object of this invention is to provide Figure 6 is an elevation of Figure 5 partly in a rugged piezo-electric crystal container which section, to show the arrangement of the heater I will be slow to respond to changes in the ambient wires within the container walls, 10

temperature due to its massive construction and Figure '7 is an amplifier circuit diagram emthe container wall thickness. bodying this invention,

A i'eature of this invention is the utilization of Figure 8 is an oscillating circuit diagram emthe heating medium as a thermal regulator and bodying the regulator of this invention,

is based upon the principles of thermal expansion Figure 9 is a tube circuit diagram in whose 15 01' fluids and Pascal's principle in obtaining a grid circuit there is located a neutralized filter, large change in fluid level in a small tube when the neutralizing condenser being actuated by the only a, small pressure is exerted in a large contemperature regulator of this invention, tainer filled with a fluid with which the smaller Figure 10 is a circuit diagram of another moditube is connected. I fication of a neutralized filter embodying the tem- 20 In temperature regulators known to the 'prior perature regulator of this invention.

, art it has been the general practice to heat the Referring now in detail to Figure 1 the heatair in a chamber, the heated air in turn heating ing wires I are shown by the sectionalized portion the thermal. regulator which controlled the heatof he container 2 to be contained within a numing-current either directly or through a relay. ber of axial apertures 3 which are filled with a 25 As it is generally well known that air is a poor non-conducting fluid 4. The non-conducting conductor of heat it is evident that there is a lag fluid is preferably one having good insulating between the heating of the air and the heating qualities and a moderate high coefiicient of exoi the regulator. Also there is a lag between the pansion such as glycerine, castor oil, liquid paraocooling of the air and the cooling of the regulaailin, kerosene, carbon tetra-chloride and the tor. This lag causes an over-travel in the heatlike. These axial apertures or tubes in the walls ing cycle and results in an inconsistency of temof cylinder 2 are also arranged in corresponding perature which causes frequency vacillation. openings in the top disk-like portion 5 and the This invention reduces the over-travel or lag bottom disk-like portion 6 of container '2. Suitas in the heating cycle to a negligible factor which able cover members 5' and 6f are provided to pro- 5 results in an improved consistency oi. frequency. tect disk-like portions 5 and 6. When the as- Briefiy, by this invention there is maintained sembly of the device is complete, the liquid ena substantial even temperature by eliminating the tirely fills all the tubes as the presence of any air lag between the heating of the air and the heatwould render this invention inoperative. Located a ing of the regulator. The heat being conducted substantially in the center of the outside of the 40 from the heating element to a cylindrical metallic container 2 are arranged two parallel columns 1 wall of substantial thickness by means of an elecand 8 (see also Figures 2 and 3). The purpose trically non-conducting fiuid. This fluid also of these columns is to provide storage space suinserves as an actuating part of the temperature ciently large so that any expansion or contracll regulator. v h tion of the fiuid in the walls of the cylinder 2 and This invention will be more thoroughly underthe top and bottom portions of the containers 5 stood by reference to the accompanying drawand 6 may be taken care of. Column 1 is at all ings in which times completely filled with a non-conducting Figure 1 is a perspective view partly in section fluid which also fills the tubes of container 2.

In of the improved temperature regulator of this in- Column 8, on the other hand, is only partly filled vention, with a fiuid, the other portion being filled with a Figure 2 is an enlarged detailed view in persmall quantity of mercury, likewise column 8 is spective also partly in section showing the exnormally open to the atmosphere. Within a centernal temperature regulatingsystem, tral portion of container 2, there is located a i Figure 3 is a detailed showing the piezo-electric crystal holder In or any other device whose temperature is desired to be maintained substantially constant. The heater wires 4 are all connected in series and are spaced as shown by Figure 4, by spacing members H which are in the form of small angles insulating the heater wire from the metal walls at such points where it is necessary to bend the heater wire around corners. The insulator II should be of any sutiable material which will not be attracted mechanically by the action of the fluid andwhich will not be dissolved in the fluid, thus causing the insulating qualities of the fluid to be lower. The size and shape of these spacing members are such as to maintain suitable clearance between the heater wires and the side of the apertures 3.

As shown in Figures 2 and 3, the heating wires are arranged with the circuit interrupting and closing device. This device is of the type having a mercury contact making and breaking a circuit arrangement which is actuated by the pressure of the heater fluid transmitted through the passage l2 to the fiuid filling tube 1 which is preferably in the form of a glass tube. A second tube 8 is positioned parallel with respect to tube I and is supported between the support members l3 and I4 which are attached to the sides of cylinder 2 by any suitable means such as bolts l5 and I6.

. The lower supporting member I4 is provided with a communicating aperture l1 and also two smaller apertures l8 and I9. These smaller apertures I 8 and I9 communicate between aperture I1 and a shallow reservoir l8 and IS in the bottom of tubes 1 and 8. In the normal operation of this device, the mercury fills the apertures ll, l8, l9 and a small globule which is located in the reservoir of tubes 1 and 8 connects with a terminal 20 which makes contact with the mercury at l9. Another terminal M is located within tube 1 and is terminated at I8.

The operating of this device is as follows:

When the temperature in the heater rises-after the proper regulating adjustments. have been made, the non-conducting fluid in the walls of the heater expands and exerts pressure in the tube I of the circuit interrupting device. This pressure displaces the level of the mercury in tube It, thus opening the circuit at the upper end of l8. As the fluid contracts due to a fall of temperature the mercury is drawn back in the aperture l8 and contact is again made. This control circuitactuates an external relay such as a thyratron vacuum tube or any other suitable relay device.

The modification shown by Figures 5 and 6 is generally similar to Figures 1 to 4 inclusive, except that the heater wires 30 are in the form of a helical coil arranged by insulating spacing members 3| located within the space formed by outer and inner containers 32 and 33. This modification is not as'complicated as that of the construction mentioned above and is generally sufficient for most all practical purposes.

Referring now to the wiring diagrams, Figures 7 to 10 inclusive, the pressure of the expanding fluid is arranged within a suitable U-shaped tube 35 to unbalance the mercury level, one column comprising one side of a condenser which may be used to vary the heating current in any suitable manner. This modification may be employed to vary the magnitude of the heating current or actually interrupting the heating circuit as mentioned above. I

Referring now in detail to Figure 7, there is shown an amplifier circuit which is provided with a suitable U-shap'ed tube 35 containing mercury 36. The outer endedl-of the U-shaped tube contains a light weight plunger 38 which rests upon the surface of the mercury so that volumetric variations in the expanding fluid will cause a movement of the mercury and the support plunger 38. The upper end of plunger 38 carries a movable part 39 which forms a plate of a small trimming condenser incorporated in a circuit 40 tuned for normal radio frequencies. If this tuned circuit is adjusted to a given point on one side of the tuning curve then any movement of the condenser plate 39 will cause a change in the tuning. The nearer the trimming condenser causes the plate circuit to be in perfect tune, the smaller will be the direct plate current. This direct plate current is also arranged to act as the heating current. Conversely, an opposite movement of the condenser will cause an increase in the direct plate current so that it will be possible toadjust the U-shaped tube assembly so that a constant heating current may flow which will generate sufficient heat to exactly balance the heat dissipating from the unit. Any tendency of the temperature within the unit to change will be compensated for by a change in the heating current.

The diagram shown in Figure 8 is that of an oscillating circuit using a small trimming condenser mentioned above with reference to Figure 7 for obtaining partial neutralization of an oscillating circuit when the condenser is located in a position such that the tube 4| is nearly neutralized, the tube will then oscillate weakly and draw a heavy direct current which is also the heating current for the control device. level of the-mercury 36 due to the expansion of the fiuid in the control device which also changes the neutralization to form values further removed from close neutralization will cause the tube to oscillate stronger and draw smaller direct current, thus reducing the heat from the heater element.

The circuit arrangement shown in Figure 9 is that of a tube circuit in whose grid circuit there is located a neutralized filter, the neutralization condenser mentioned above being actuated by the mercury level by means of expansionof the fiuid in the control device. When the condensers on each side of the secondary, of radio frequency transformer 48 are unbalanced there will be an excitation on the grid of the tube so that the tube will then conduct, drawing current which passes through the heater element. As the capacity of the variable condenser approaches the capacity of a fixed condenser 41 on the opposite side of the transformer secondary, the current impulse will be balanced out and the tube will not draw any load, thus causing a change in the heat from the heater current as there is no excitation and no current passing through the tube.

In the circuit diagram shown in Figure 10, another neutralized filter arrangement is located in the grid circuit of a tube whose plate current passes through the heater element in this circuit arrangement. Instead of the capacities being on each side of the secondary of the radio frequency transformer, there is a fixed resistance 42 on one side, the other side being a variable resistance within the U-shaped tube, the inner walls of which A change in the y are metallized at 43 so that the inner surface is a high resistance conductor. When the expanding fluid causes an unbalance in the mercury this combination is unbalanced, the tube draws a loadcurrent and when the resistances closely approach a balance the tube current is then cut off.

By these circuit diagrams it has been shown how a modification of this invention may be utilized to control the temperature by means of electron discharge devices other than those of the thyratron-type relay circuits. It is to be pointed out that a functional feature of this control device is that the heater element is located in the fluid container 2 whose coeflicient of expansion is large compared with that of the actual actuating element of the regulating thermostat itself.

This invention should not be limited to the specific modifications described but only by such limitations as are clearly imposed in the appended claims.

We claim: i Q

l. A temperature regulating device comprising a container, a plurality of apertures within the walls of said container, heater wires located within said apertures, a non-conducting fluid surrounding said wires and in fluid communication with an expanding fluid type of temperature regulating device located external 01 said container, an external current supply for heating said wires, said regulating device electrically connected with said heater wires and said external electrical supply circuit to control the temperature within said container.

2..A temperature regulating device comprising a metallic container, a plurality of axial apertures within the walls ofsaid container, heater wires located within said apertures, said wires being spaced from said containeriby a plurality of insulating members, a fluid surrounding said wires and said insulating members and in fluid communication with a fluid expanding type of heat regulating device located external of said container, said heat regulating device connected with said heater wires and an external source of current to control the temperature within said container by the expansion and contraction of said fluid. v

3. A temperature regulating device comprising a metallic container, a plurality of apertures within the walls of said container, heater wires located within said apertures, electrical means for heating said wires, a fluid expanding type of heat regulating device located external of said container, said regulating device comprising two parallel arranged tubes, the top end of one of said tubes being in fluid communication with said container, and the top end of the other tube being open to atmosphere, an electrical contact member located at the bottom of both of said tubes, and a fluid passage connecting said tubes together, a quantity'oi mercury in said fluid passage and arranged to make electrical contact with both contact members, fluid communication means between the container and said temperature regulator, said heat regulating device being electrically connected with said heater wires and an external electrical supply source to control the temperature within said container.

4. A temperature regulating device comprising a metallic container, a plurality of cylindrical apertures within the walls of said container, heating wires located within said cylindrical apertures, electrical means for heating said wires, a fluid expanding type of temperature control device wherein said heating wires are surrounded by the fluid of said temperatmecontrol device, said fluid serving as one element of said fluid expanding temperature control device, said device being located external of said container, said fluid expanding temperature control device being v connected with said heater wires and an external source to control the temperature within said container.

5. A temperature regulating device comprising a metallic container, a plurality of apertures within the walls of said container, a heating element within said apertures, an expanding fluid surrounding said heating element and serving as one element of a thermostat and a means for conducting heat to the walls of said container, means for heating said wires, a heat regulating device located external of said container, said heat regulating device connected with said heater wires and an external device to control the temperature within said container.

6. A temperature control device comprising a cylindrical container, a heating element located in a plurality of apertures within said container, said heating element being in combination with a fluid expanding type of circuit opening and closing device, a fluid surrounding said heater wires, said fluid being in fluid communication with said opening and closing device so that compensation will result from a tendency of any change in the ambient temperature to cause a change in the temperature in the space within said control device 7. A temperature control device comprising a container, a heating element located within said container, a fluid expanding type of heat regulating device located external of said container cuit said trimming condenser having a flxed and movable plate the movable plate being secured to said float member to vary the condenser in the tuned circuit upon a change in temperature.

8. A temperature control device comprising. a container, a heating element located within said container, a fluid expanding type of heat regulating device located external of said container comprising a U-shaped tube containing mercury, a float member floating on the top of said mercury, an oscillator circuit connected with said heat regulating device to regulate the heat within said container by means of a variable trimming condenser incorporated in a tuned circuit of said oscillator, said trimming condenser having a fixed and movable plate, the movable plate being secured to said float member to vary the condenser in the oscillating circuit upon a change in temperature.

9. A temperature control device comprising a container, a heating element located within said container, a fluid type of heat regulating device and a heat supply source located external of said container, an electron tube circuit comprising a. neutralized fllter, a U-shaped tube forming a metallized resistor being actuated by the expansion of the fluid within said control device, said resistor being arranged in the grid circuit of said electron discharge tube so that the tube plate circuit is made responsive to vary said heat supply source.

10. A temperature control device comprising a container, a heating element located within said container, a fluid type of heat regulating device located external of said container, a U- whereby the capacity of said condenser unbalances the filter circuit and plate current passes through the heater element to control the temperature within said container.

LLOYD L. YOUNG. JAMES LESLIE FINCH. 

